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Climate in Cities
basics
1. Air Pollution
2. Urban Climate
3. Acid Rain
- What is it?
- Impact 1
- Areas in danger
* Worksheet 1
* Worksheet 2
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climate in cities

Climate in cities

Basics


3. Acid rain


Worksheet 2:
Rain water and its acid properties

 

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This worksheet will help you look at rainwater acidity and how acid rain affects calcium carbonate containing rocks like marble and limestone.

 

You will need the following materials and chemicals for the experiments:

 

Funnel and bottle to collect rainwater with

 

pH meter or narrow range pH paper

 

small glass beaker or watch glass

 

pieces of marble (with a solid structure, not porous or crumb-like)

 

100 mL beaker

 

water

1

hair-dryer

 

diluted nitric acid (2N)
[C; R: 35; S: 23-26-36/37/39]

1

high-precision balance

  plastic bottles to collect water samples in

 

Device to collect rain water

Figure 1: Device to collect rain water
                    © 2004 M. Seesing

E1

Collect one or more rainwater samples.  Each sample needs to be at least 50 mL in volume.  Use the set up shown in Figure 1. to collect your samples.

Collect other water samples such as drinking water, water from a pond and seawater for comparison.

 

E2

Put a few mL of your rain water into a clean beaker or on a clean watch glass and measure the pH. Do the same with your other samples. This prevents your samples getting contaminated.

Write your results in the table below.

 

 

No.

sample (origin)

pH value

 

No.

sample (origin)

pH value

1

 

   

5

   

2

 

   

6

   

3

 

   

7

   

4

 

   

8

   

E3

Put 50 mL of your rainwater into a high 100 mL beaker.  Put the same amount of 2N Nitric acid into another 100 mL beaker.  Measure the pH values of the solutions with a pH meter or narrow range pH paper.  Find two pieces of marble which each weigh about 6 g.  Make a note of the exact weight of each piece of marble.  Add the marble pieces to the solutions. Make sure the pieces of marble are completely covered by the liquids. Cover the beakers with watch glasses and watch what happens to the pieces of marble.

  1. Write your results in the table below.
  2. Note down your observations below the table.
  3. After approximately 10 minutes, test the gas in the beakers with a burning wood stick and see if it burns.
  4. After 15 minutes take the pieces of marble out of the solution, rinse them thoroughly with deionized water and dry them with a hair-drier. Then weigh them accurately.
  5. Measure the pH of the remaining solutions.
  6. Put the marble pieces back into the solutions and cover the beakers with watch glasses. After a few days clean, dry and weigh the pieces of marble again and measure the pH values of the solutions.

 

measurement 1

measurement 2

solution tested

   

mass of the piece of marble 
before the experiment

   

pH value of the solution 
before the experiment

   

mass of the piece of marble 
after 15 min

   

pH value of the solution 
after 15 min

   

mass of the piece of marble 
after ___ days

   

pH value of the solution 
after ___ days

   

The gas inside the beaker:

®burns

®puts out the flame

®none of the above

®burns

®puts out the flame

®none of the above

 

About this page:
authors: M. Seesing, M. Tausch - Universitšt Duisburg-Essen, Duisburg, Germany
last update: 2004-05-24

 

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last updated 02.03.2006 21:34:00 | © ESPERE-ENC 2003 - 2013